DE 2431937 A1 in the name of Sennheiser Electronic KG describes the use of multi-channel infrared transmission of audio feeds in different languages from interpreters at a conference to receivers in headsets worn by conference delegates.
International standard IEC 61603-7, entitled “Transmission systems of audio and/or video and related signals using infra-red radiation— Part 7: Digital audio signals for conference and similar applications”, describes the characteristics of a digital multiple channel, multiple carrier audio transmission system as an extension to conference interpretation or similar systems using the frequency ranges 45 kHz to 1 MHz and 2 MHz to 6 MHz.
It is a disadvantage of the known, standardized systems that the number of channels that can be transmitted is limited to 24 audio channels (6 infrared channels, with 4 audio channels each). Some system vendors have taken advantage of the structure of the IEC 61603-7 configuration message to signal the presence of up to 32 channels. Given the fact that the field used for signaling the number of audio channels in the standardized configuration message is 5 bits, 32 audio channels has been considered to be the maximum number that could be announced in a vendor-proprietary way without completely losing backward compatibility with standardized systems.
It is a purpose of embodiments of the present invention to overcome this limitation, without completely losing backward compatibility with standardized systems.